1. Technical Field
The present invention relates to a defect register method for registering each address of defective sectors arising in a data recording medium, such as a disk recording medium, in a defect map, a recording medium in which the defect map is registered and which is computer-readable, and a disk apparatus that refers to the defect map where addresses of defective sectors in the disk recording medium are registered and accesses the disk recording medium.
2. Description of the Related Art
Each surface of a disk (disk recording medium) in a disk apparatus is divided into a plurality of tracks, and each track is divided into a plurality of sectors. The disk apparatus refers to a defect map where addresses of defective sectors are registered, accesses a non-defective sector with a read/write head that is provided for every disk surface, and writes data in the sector or reads data from the sector. The defect map is classified into a primary defect map (PDM) and reassign defect map (RDM).
Each sector in the disk apparatus has an absolute block address (ABA). In addition, each head and disk surface has a head identification number HED, each track on a disk surface has a cylinder identification number CYL, and each sector in a track has a sector identification number SEC. The disk apparatus identifies a track by the HED and CYL.
When formatting a disk, the disk apparatus inspects all sectors, generates a PDM where positional information of defective sectors (initial defective sectors) is registered, and records this PDM in a map recording medium (a system reserve region that is part of the disk, a nonvolatile semiconductor memory apparatus, or the like). A logical block address (LBA) is assigned to a normal sector that is not registered in the PDM. The positional information registered in the PDM is an ABA or false logical block address (F.LBA) of an initial defective sector. The F.LBA is an LBA that would be assigned if the defective sector were normal.
In addition, if a defective sector (a subsequent defective sector) arises after the completion of formatting, the disk apparatus performs alternative processing of this subsequent defective sector. Furthermore, the disk apparatus registers an LBA of the subsequent defective sector and an LBA of an alternative sector in the RDM, and records this RDM in the map recording medium.
FIG. 12 is an example of initial defective sectors in a track that is part of a disk. In FIG. 12, xe2x80x9cxxe2x80x9d shows an initial defective sector. In addition, let a track having a cylinder identification number CYL and a head identification number HED be T(CYL, HED). T(1, 0) means a track of CYL=1 and HED=0. In addition, ABA are assigned in the order of tracks T(0, 0), T(1, 0), T(2, 0), . . . Furthermore, each sector length (the number of sectors) T.LE of tracks T(0, 0), T(1, 0), T(2,0) is 10. Moreover, FIG. 12 is just a schematic drawing, and the T.LE described above is, for example, 200 to 400 in an actual disk apparatus.
FIGS. 13A to 13C are explanatory diagrams of the structure of PDM generated for the initial defective sectors, shown in FIG. 12, in a conventional disk apparatus.
FIG. 13A shows the PDM where an absolute block address of each initial defective sector (D.ABA) is individually registered.
Nevertheless, since the memory capacity of an entire disk apparatus sharply increases recently, a total number of defective sectors also increases with relation to that. Therefore, a data amount of the PDM in FIG. 13A where each defective sector is individually registered becomes huge. In a current disk recording medium having high recording density, such a probability that defective sectors are continuous is high, and hence a PDM where each series of defective sectors with continuous ABA is registered in a batch by registering a position and sector length (the number of sectors) of the series of defective sectors is devised as shown in FIGS. 13B and 13C.
FIG. 13B shows a PDM where a series of defective sectors consisting of defective sectors with continuous ABA is registered in a batch by registering a first absolute block address of the series of defective sectors (D.ABA.ST), and defective sector length of the series of defective sectors (D.LE). In addition, FIG. 13C shows a PDM where a series of defective sectors consisting of defective sectors with continuous ABA is registered in a batch by registering a false logical block address of the series of defective sectors (F.LBA), and defective sector length of the series of defective sectors (D.LE) In FIGS. 13B and 13C, two defective sectors, which have continuous ABA and have register numbers X of 0 and 1, shown in FIG. 13A, respectively, are registered in a batch at the register number Y=0. Furthermore, four defective sectors, which have continuous ABA and have register numbers X of 2 to 5, shown in FIG. 13A, respectively, are registered in a batch at the register number Y=1.
Furthermore, a data amount of the PDM is reduced by dividing the D.ABA.ST or F.LBA into upper bits and lower bits, registering the upper bits in a virtual track table (VTT), and registering the lower bits and D.LE described above in a virtual sector table (VST).
The disk apparatus obtains a track (CYL and HED where the LBA described above exists), where an LBA that the disk apparatus is requested by a host system to access exists, with referring to the PDM. Next, the disk apparatus generates an ID table (a table for associating a SEC of each sector and the LBA assigned) of this track with referring to the PDM. Then, by referring to this ID table, the disk apparatus accesses the sector having the LBA requested. In addition, if the alternative processing was performed to the LBA requested, the disk apparatus accesses its alternative sector with referring to the RDM.
The processing to assign an LBA is just the processing of generating an ID table with referring to a PDM. It is conceivable that after generating the PDM, the disk apparatus generates the ID table of all the tracks and records this ID table of all the tracks in a system reserve region and the like. Nevertheless, since a data amount of the ID table of all the tracks is huge, it is not desirable to record the ID table of all the tracks in a system reserve region and the like. For this reason, the disk apparatus generates an ID table of a track, being accessed, on each occasion. If the contents of the PDM are the same, an ID table having the same contents is generated for every access.
Nevertheless, in the conventional PDM where the initial defective sectors with continuous ABA are registered in a batch, there is such a possibility that a normal sector that is not registered in a PDM is erroneously made to be defective when an LBA is assigned by generating an ID table of a track. Therefore, in order to avoid such a case, it becomes necessary to impose a burden on another mechanism such as modification of a disk controller (hardware comprising a logic circuit and a counter circuit), or defect correction by a micro processing unit (MPU). Thus, even if a data amount of the PDM can be reduced, it is obliged to modify another mechanism for the sake of that, and complicated processing is required.
FIGS. 14A to 14C are explanatory diagrams of track ID tables generated for initial defective sectors, shown in FIG. 12, in a conventional disk apparatus. FIG. 14A shows an ID table of the track T(0, 0), FIG. 14B shows an ID table of the track T(1, 0), and FIG. 4C shows an ID table of the track T(2, 0). In addition, xe2x80x9cxxe2x80x9d represents a SEC to which an LBA is not assigned.
If a series of initial defective sectors passing over tracks is registered in a batch in a PDM, it arises that an LBA is not assigned to each of sectors in spite of the sectors being not registered in the PDM. For example, if a series of initial defective sectors passing over tracks such as the initial defective sectors having ABA=8, . . . , 11 in FIG. 12 is registered in a batch at the register number Y=1 in the PDM shown in FIG. 13C, the ID table of the track T(1, 0) is generated as shown in FIG. 14B. Therefore, normal sectors having ABA=12, 13 are made to be defective.
An ID table is generated by a control unit of a disk apparatus. This control unit comprises an MPU and a disk controller (hardware comprising a logic circuit, a counter circuit, and the like). The MPU obtains a minimum logical block address in a track (MIN.LBA) and sector length (the number of sectors) in the track (T.LE). In addition, the MPU discriminates register numbers in the PDM to refer to, sends these as ID table information to the disk controller, and instructs generation of ID tables.
In regard to an ID table of the track T(0, 0), the disk controller generates the ID table as shown in FIG. 14A according to such ID table information that the MIN.LBA is 0, T.LE is 10, and the register number Y in the reference PDM is 0.
In this case, the disk controller assigns MIN.LBA=0 to the sector with SEC=0, and assigns LBA=1 to the sector with SEC=1. Next, since F.LBA=2 and D.LE=2 are registered at the register number Y=0 in the PDM shown in FIG. 13C, the disk controller assigns LBA=2 to the sector with SEC=4 with skipping the sectors SEC=2 and 3. Then the disk controller increments the register number Y to 1. Next, the disk controller assigns LBA=3, 4, 5 respectively to the sectors SEC=5 to 7 in order. Furthermore, since F.LBA=6 and D.LE=4 are registered at the register number Y=1 in the PDM shown in FIG. 13C, the disk controller skips the sections SEC=8 and 9. Since the sector with SEC=9 is the end sector of the track (EOT: End Of Track) T(0, 0), the disk controller finishes the generation of the ID table of the track T(0, 0) after skipping the sector with SEC=9.
In addition, in regard to an ID table of the track T(1, 0), the disk controller generates the ID table as shown in FIG. 14B according to such ID table information that the MIN.LBA is 6, T.LE is 10, and the register number Y in the reference PDM is 1.
In this case, since F.LBA=6 and D.LE=4 are registered at the register number Y=1 in the PDM shown in FIG. 13C, the disk controller assigns MIN.LBA=6 to the sector with SEC=4 with skipping the sectors SEC=0 to 3. For this reason, the disk controller does not assign LBA to normal sectors SEC=2 and 3 that are not registered in the PDM. After this, the disk controller assigns LBA=6, . . . , 11 respectively to the sectors SEC=4 to 9 in order. Since the sector with SEC=9 is an EOT, the disk controller finishes the generation of the ID table of the track T(1, 0) after assigning LBA=11 to the sector with SEC=9.
In addition, in case of an ID table of the track T(2, 0), the disk controller generates the ID table as shown in FIG. 14C according to such ID table information that MIN.LBA is 14, T.LE is 10, and the register number Y in the reference PDM is 2.
Up to the sector with SEC=7 in the track T(0, 0), discrepancy between the ABA and LBA is equal to the number of initial defective sectors existing before the sector, and hence it is possible to obtain the discrepancy by simply accumulating the defective sector length D.LE in the PDM. Nevertheless, after the sector with SEC=4 of the track T(1, 0), it should be performed to consider the number of sectors that are not registered in the PDM and that LBA are not assigned to, so as to obtain the discrepancy between the ABA and LBA.
In order to obtain a track where an LBA that the disk apparatus is requested by a host system to access exists, the control unit transforms the LBA described above into an ABA with referring to the PDM, and transforms this ABA into CHS (CYL, HED, and SEC) by calculation.
For example, if transforming the LBA=10 into an ABA, the control unit transforms F.LBA[0]=D.ABA.ST[0]=2 (at Y=0, F.LBA=D.ABA.ST) into CHS with reference to Y=0 in the PDM shown in FIG. 13C. Furthermore, the control unit judges whether the series of defective sectors at Y=0 passes over tracks. In this case, since the series of defective sectors does not pass over the tracks, the control unit judges that the discrepancy between the ABA and LBA due to the series of defective sectors at Y=0 is equal to D.LE[0]=2.
Next, the control unit transforms F.LBA[1]=6 into the D.ABA.ST with referring to Y=1 in the PDM shown in FIG. 13C. In consequence, D.ABA.ST[1]=F.LBA[1]+D.LE[0]=8. Furthermore, the control unit transforms D.ABA.ST[1]=8 into a CHS, and judges whether the series of defective sectors at Y=1 passes over tracks. In this case, the series of defective sectors passes over the tracks T(0, 0) and T(1, 0), and two sectors out of four defective sectors at Y=1 exist in the track T(1,0). Hence the control unit judges that the discrepancy between the ABA and LBA due to the series of defective sectors at Y=1 is D.LE[1]+2=4.
Therefore, the control unit adds D.LE[0]+D.LE[1]+2=8 to the LBA whose value is 10, and judges that the ABA of the LBA whose value is 10 is 18.
In this manner, when an ID table is generated with referring to such a conventional PDM that a series of initial defective sectors with continuous ABA is registered in a batch, LBA may not be assigned to sectors that are not defective if there is a series of defective sectors passing over tracks. In addition, if the control unit refers to the conventional PDM, the control unit should judge whether each series of defective sectors registered in the PDM passes over tracks when performing the LBA/ABA transformation and ABA/LBA transformation. Therefore, since the control unit should also perform the ABA/CHS transformation for this judgment, the LBA/ABA transformation and ABA/LBA transformation become complicated.
It is possible to make the disk controller or MPU judge whether a series of defective sectors having a PDM register number (a reference PDM register number that is included in ID table information sent from the MPU) to which the disk controller first refers when generating the ID table passes over tracks. Owing to this, it is not impossible to avoid the occurrence of a sector to which an LBA is not assigned in spite of a normal sector even if the series of defective sectors passes over tracks.
Nevertheless, in a current disk apparatus, since multi-zone recording or banded zone format is adopted, the calculation of the ABA/CHS transformation is complicated. Therefore, it is not realistic to make the disk controller, which is hardware, judge whether a series of defective sectors having a PDM register number to which the disk controller first refers passes over tracks. In addition, it should be performed for every generation of an ID table to judge whether a series of defective sectors having a PDM register number to which the disk controller first refers passes over tracks. Therefore, although it is possible to make the MPU perform this, the calculation by the MPU is inserted for every generation of an ID table. Hence, since command overhead (time from when a disk apparatus receives a command from a host system to when the disk apparatus starts accessing a medium) becomes large, the performance of the disk apparatus decreases.
In addition, the multi-zone recording is a method for locating sectors so that the number of sectors per track may become larger as a zone is nearer to the outer edge of a disk, by dividing a disk surface into a plurality of zones and changing the number of sectors per track for every zone. Furthermore, the banded zone format is a method for assigning ABA sequentially from an outmost band so that the number of head changes may become the fewest, by dividing a disk into a plurality of bands (one band is composed of, for example, 64 cylinders).
Moreover, in an RDM, it is necessary to register not only an LBA of a subsequent defective sector, but also an LBA of the corresponding alternative sector. For this reason, if the above-described conventional defect map in which a series of defective sectors that is continuous is registered in a batch is applied to the RDM, LBA of the corresponding alternative sectors are not always continuous even if LBA of the subsequent defective sectors are continuous. Therefore, registration contents of the alternative sectors become complicated. For this reason, the processing when the control unit accesses the alternative sectors with referring to the RDM becomes complicated.
As described above, in the conventional defect map, there are themes to be pursued in regard to increasing process performance at the time of a disk access as follows: (1) to eliminate a disadvantage of erroneously making a normal sector defective, and (2) to simplify the processing of generating an ID table.
An object of the present invention is to provide defect map structure that can increase the process capability of a recording apparatus when accessing a data recording medium.
In order to achieve the above object, a defect register method according to the present invention comprises the steps of:
(A) discriminating a series of defective sectors consisting of a plurality of defective sectors with continuous addresses, the plurality of defective sectors meeting a predetermined condition with respect to a partial region where the defective sectors are located or alternative sectors which correspond to the defective sectors, and
(B) registering the series of defective sectors in a defect map by registering a first address and sector length of the series of defective sectors.
Further, specifically, the step (A) is a step of discriminating a series of defective sectors consisting of a plurality of defective sectors with continuous addresses, the plurality of defective sectors that exist in the same partial region.
Alternatively, the step (A) is a step of discriminating a series of defective sectors consisting of a plurality of defective sectors with continuous addresses, the plurality of defective sectors whose alternative sectors have continuous addresses.
Furthermore, the step (B) is a step of registering in a defect map the series of defective sectors and a series of alternative sectors that correspond to the series of defective sectors by registering each first address and sector length of the series of defective sectors and the corresponding series of alternative sectors.
A defect map recording medium according to the present invention records a defect map where a series of defective sectors consisting of a plurality of defective sectors with continuous addresses, the plurality of defective sectors meeting a predetermined condition with respect to a partial region where the defective sectors are located or alternative sectors which correspond to the defective sectors, is registered by a first address and sector length of the series of defective sectors being registered.
Further, specifically, the defect map recording medium described above records a defect map where a series of defective sectors consisting of a plurality of defective sectors with continuous addresses, the plurality of defective sectors which exist in the same partial region, is registered by registering a first address and sector length of the series of defective sectors.
Alternatively, the defect map recording medium described above records a defect map where a series of defective sectors consisting of a plurality of defective sectors with continuous addresses, the plurality of defective sectors whose alternative sectors have continuous addresses, and the series of alternative sectors which correspond to the defective sectors are registered by registering each first address and sector length of the series of defective sectors and the corresponding series of alternative sectors.
A disk apparatus according to the present invention comprises a disk recording medium which is divided into a plurality of tracks each of which is divided into a plurality of sectors, a defect map storage medium where a defect map where addresses of defective sectors in the disk recording medium are registered is recorded, disk access means for writing data into and reading data from the sectors in the disk recording medium, and disk access control means for referring to the defect map and making the disk access means access normal sectors, wherein a series of defective sectors consisting of a plurality of defective sectors with continuous addresses, the plurality of defective sectors which exist in the same track, is registered in the defect map by a first address and sector length of the series of defective sectors being registered.
In addition, another disk apparatus according to the present invention comprises a disk recording medium which is divided into a plurality of tracks each of which is divided into a plurality of sectors, a defect map storage medium where a defect map where positions of defective sectors in the disk recording medium are registered is recorded, disk access means for writing data into and reading data from the sectors in the disk recording medium, and disk access control means for referring to the defect map and making the disk access means access normal sectors, wherein a series of defective sectors consisting of a plurality of defective sectors with continuous addresses, the plurality of defective sectors whose alternative sectors have continuous addresses, and a series of alternative sectors which correspond to the defective sectors are registered in the defect map by each first address and sector length of the series of defective sectors and the corresponding series of alternative sectors being registered.